P0455 and P0441

I have a new gas cap and tested the valve under the hood and it's good (pulled the hose coming from the tank and the valve started going thump thump thump after a few minutes of engine running).

Is there another valve somewhere? Does the charcoal canister have separate parts that can be replaced individually?

Assuming I don't have a torn hose or rodent damage at the top of the tank (will visually inspect soon).

I also have P0171 and P0174 which makes me fear the rodent damage.

 

another update. I ran a smoke machine at the purge valve (the one under the hood on top of the intake manifold) on the hose that runs to the fuel tank. the smoke was coming out of the gas cap and two little holes at the filler neck. is this normal venting? didn't see smoke anywhere else.

 

PS I just realized the system is open when the car isn't running... I will look into how to close it.

 

What you are seeing is the vent for the canister which sits on the filler pipe up near the gas cap. Since you did not command the vent valve closed the smoke is coming out of the evap filter that you have pictured. It should not be coming out of the gas cap as it's a sealed unit and does not vent. The system is open when running. But the purge is closed so it has no affect on the engine running. If it wasn't open at the vent the tank would balloon or collapse. The evap system has 2 valves, purge and vent. The purge is normally closed and the vent is normally open. The purge is opened when the ECM purges the canister's vapors. The vent is only closed for diagnostic purposes. (to seal the system). In place of commanding the vent closed you could plug of or if there is a rubber hose pinch off the vent line coming out of the canister. Now your smoke would be forced to come out any leak. Quite possibly the purge valve is sticking open. Toyota purge valves have sticking in their DNA it seems. When the purge is supposed to be closed but is stuck open it creates a gross leak (P0455) and can cause a lean condition (P0171,P0174). And of course incorrect purge flow (P0441). Usually this happens at idle since going down the road the purge is likely open by the ECM by programming.

 

I closed off the vent that was by the gas cap and it started coming out of the cap... but I also just replaced the cap... bad new cap???

purge valve tested good.

 

A purge valve can test "good". But after driving and it warms up or whatever it can stick. If not an new OE cap probably bad. No cap should leak. Maybe the seal surface on the filler neck nicked or dented. Or a damaged O-ring? I've replaced many purge valves that are good, in the shop, while I was testing them. You have to catch it stuck after driving. usually the datastream shows a severe lean condition. (high fuel trim numbers)

 

High trim lean is what I had. I'll try OEM cap from the dealer and a new valve.

 

So this is crazy, but the problem seems to have resolved itself. I filled my tank this morning expecting to do the long crank and wait, but it started right up no problem. I also haven't had any weird codes pop back up. Is it possible that just messing with the hoses sealed up any leak? Good bad gas have caused all of this?

 

Long crank and wait? This is new info. I'm assuming you don't have a 3UR-FBE engine.....which has it's own reason for extended crank time. So say a purge solenoid is sticking open. You gas up your vehicle. The vapors in addition to exiting your tank through the canister vent it now can also exit through the purge valve into the intake manifold and flood it with fuel laden vapors. Now you get an extended crank, as it's overly rich, and when it does start it typically runs rough for a bit and often it may puff out a small cloud from the exhaust. That being said your initial description in addition to being vague about the symptoms is lacking outer symptoms happening. Does it ever idle rougher than normal when coming to a stop after cruising? Either from highway or steady in town speeds? And no, dinking with hoses would not cure a gross (very large) leak. Unless messing with them included cutting out a split portion or reattaching a hose that has come off.

 

I replaced my fuel cap with a locking one from Autozone. Immediately started getting evap codes, would then get them every few days but ran with it for awhile. suspected it was the fuel cap right from the beginning. finally replaced with an OEM fuel cap, codes gone.